Methods for extending a selector application programming interface and devices thereof

ABSTRACT

A method, non-transitory computer readable medium, and web content management server device that receives a cascading style sheet (CSS) selector expression comprising a plurality of expression components. Whether an equivalent XML path language (XPath) expression can be generated for each of the expression components is determined. Each of the expression components for which an equivalent XPath expression cannot be generated is transformed into a transformed expression comprising at least one XPath expression and an extension function.

FIELD

This technology generally relates to methods and devices for optimizingdelivery of web content and, more particularly, to methods for extendinga selectors application programming interface (API) and devices thereof.

BACKGROUND

A web content management server is a server that optimizes web pages andweb page interactions for client devices with special requirements, suchas smartphones. By way of example, a client device can send an HTTPrequest for a web page which is retrieved from a server device by theweb content management server. Next, the web content management servercan optimize the content of the web page by applying transformationrules tailored to the requesting client device. This optimizationprocess can include extracting content relevant to the requesting clientdevice and adapting the extracted content to fit the specifications ofthe requesting client device. In order to adapt the content, the webcontent management server can perform transformations includingJavaScript removal, content linearization, and small screen adaptation,for example.

Although this process works well to optimize content for display at therequesting client device, the web page may not function properly whenthe original content heavily depends on JavaScript technology thatcannot be implemented on some client devices. For example, if therequested web page includes JavaScript code responsible for populatingform fields, validating form submissions, retrieving data from externalresources (e.g., based on AJAX technology), and even generatingcomponents that may change the structure of the web page, the page atthe client device will not be able to properly function.

Accordingly, JavaScript included in web pages can be removed, stored bythe web content management server, and replaced by a hidden field withan identifier, for example. The identifier is subsequently sent by theclient device in an HTTP request in response to a web page interactionrequiring execution of the JavaScript, such as a request for validationof login credentials. Based on the identifier, the web contentmanagement server can retrieve the JavaScript, execute the JavaScript inan emulated JavaScript environment on behalf of the client device, andreturn a result to the client device.

In some implementations, the emulated JavaScript environment can supportapplication programming interfaces (APIs) such as those defined byhypertext markup language (HTML), events, cascading style sheet (CSS),range, traversal, and views models, for example. Some of the supportedAPIs can allow web page developers to embed JavaScript definingfunctionality for accessing a document object model (DOM) associatedwith a web page in order to perform an operation. For example, theselector API provides CSS selector expressions or queries configured tobe applied to a DOM to obtain a result set of elements of the DOM.

However, CSS selector expressions can be difficult to implement, can becomplex, and can require specific code or libraries to be implemented.While some CSS selector expressions can be translated into XML pathlanguage (XPath) expressions or queries, which are relatively efficientto execute, many CSS selector expressions are not translatable.

SUMMARY

A method for extending a selector application programming interface(API) includes receiving, with a web content management server, acascading style sheet (CSS) selector expression comprising a pluralityof expression components. Whether an equivalent XML path language(XPath) expression can be generated for each of the expressioncomponents is determined with the web content management server. Each ofthe expression components for which an equivalent XPath expressioncannot be generated is transformed with the web content managementserver into a transformed expression comprising at least one XPathexpression and an extension function.

A non-transitory computer readable medium having stored thereoninstructions for extending the selector API comprising machineexecutable code which when executed by a processor, causes the processorto perform steps including receiving a cascading style sheet (CSS)selector expression comprising a plurality of expression components.Whether an equivalent XML path language (XPath) expression can begenerated for each of the expression components is determined. Each ofthe expression components for which an equivalent XPath expressioncannot be generated is transformed into a transformed expressioncomprising at least one XPath expression and an extension function.

A web content management server device includes a processor coupled to amemory and configured to execute programmed instructions stored in thememory including receiving a cascading style sheet (CSS) selectorexpression comprising a plurality of expression components. Whether anequivalent XML path language (XPath) expression can be generated foreach of the expression components is determined. Each of the expressioncomponents for which an equivalent XPath expression cannot be generatedis transformed into a transformed expression comprising at least oneXPath expression and an extension function.

This technology provides a number of advantages including methods,non-transitory computer readable medium, and devices that facilitatemore efficient processing of CSS selector expressions using XPath. Withthis technology, CSS selector expressions are fully translatable intoXPath expressions which can be evaluated in an emulated JavaScriptenvironment by a relatively efficient XPath processor without requiringthe specific code otherwise necessary to execute the CSS selectorexpressions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a network environment with an exemplary webcontent management server;

FIG. 2 is a flow chart of an exemplary method for extending the selectorAPI to an emulated JavaScript environment;

FIG. 3 is a flow chart of an exemplary method performed by an extensionfunction for evaluating the :first-of-type, :last-of-type, :nth-of-type,and :nth-last-of-type pseudo classes;

FIG. 4 is a flow chart of an exemplary method performed by an extensionfunction for evaluating the :last-of-type, :only-of-type, and:nth-last-of-type pseudo classes;

FIG. 5 is a flow chart of an exemplary method performed by an extensionfunction for evaluating the :lang pseudo class;

FIG. 6 is a flow chart of an exemplary method performed by an extensionfunction for evaluating the :not pseudo class; and

FIG. 7 is a flow chart of an exemplary method performed by an extensionfunction for evaluating the :selected jQuery pseudo class.

DETAILED DESCRIPTION

An exemplary network environment 10 with a web content management server12 coupled to client devices 14(1)-14(n) and server devices 16(1)-16(n)is illustrated in FIG. 1. In this example, the web content managementserver 12, client devices 14(1)-14(n), and server devices 16(1)-16(n)are coupled together by communication networks 18(1)-18(2), althoughother numbers and types of systems, devices, and/or elements in otherconfigurations or network topologies can also be used. This technologyprovides a number of advantages including methods, non-transitorycomputer readable medium, and devices that facilitate more efficientprocessing of CSS selector expressions in an emulated JavaScriptenvironment.

The web content management server 12 is coupled to the client devices14(1)-14(n) by the communication network 18(1), which can include one ormore local area network(s) (LANs) and/or wide area network(s) (WANs). Inthis example, the web content management server 12 is further coupled tothe server devices 16(1)-16(n) by the communication network 18(2), whichmay also include one or more LANs and/or WANs. Other network devicesconfigured to generate, send, and receive network communications andcoupled together via other topologies can also be used. While not shown,the network environment 10 also may include additional networkcomponents, such as routers, switches and other devices, which are wellknown to those of ordinary skill in the art and thus will not bedescribed here.

The web content management server 12 may perform any number of functionsincluding optimizing content retrieved from the server devices16(1)-16(n) for display on the client devices 14(1)-14(n), for example.In this example the web content management server 12 includes aprocessor 20, a memory 22, and a communication interface 24, which arecoupled together by a bus 26 or other link, although other numbers andtypes of components, parts, devices, systems, and elements in otherconfigurations and locations can be used.

The processor 20 in the web content management server 12 executes aprogram of stored instructions one or more aspects of the presentinvention, as described and illustrated by way of the embodimentsherein, although the processor 20 could execute other numbers and typesof programmed instructions. The processor 20 of the web contentmanagement server 12 may comprise one or more central processing unitsor general purpose processors with one or more processing cores, forexample.

The memory 22 in the web content management server 12 stores theseprogrammed instructions for one or more aspects of the presentinvention, as described and illustrated herein, although some or all ofthe programmed instructions could be stored and/or executed elsewhere. Avariety of different types of memory storage devices, such as a randomaccess memory (RAM) or a read only memory (ROM) in the system or afloppy disk, hard disk, CD ROM, DVD ROM, or other computer readablemedium which is read from and/or written to by a magnetic, optical, orother reading and/or writing system that is coupled to the processor 20,can be used for the memory 22 in the web content management server 12.

The communication interface 24 in the web content management server 12is used to operatively couple and communicate between the web contentmanagement server 12, client devices 14(1)-14(n), and server devices16(1)-16(n), which are all coupled together via the communicationnetworks 18(1)-18(2), although other types and numbers of communicationnetworks or systems with other types and numbers of connections andconfigurations to other devices and elements can also be used. By way ofexample only, the communication networks 18(1)-18(2) can use TCP/IP overEthernet and industry-standard protocols, including hypertext transferprotocol (HTTP), secure HTTP (HTTPS), wireless application protocol(WAP), and/or SOAP, although other types and numbers of communicationnetworks, such as a direct connection, modems and phone lines, e-mail,and wireless and hardwire communication technology, each having theirown communications protocols, can be used.

The client devices 14(1)-12(n) enable a user to request, receive, andinteract with applications, web services, and content hosted by theserver devices 16(1)-16(n) through the web content management server 12and using the communication network 18(1), although one or more of theclient devices 14(1)-14(n) could access content and utilize other typesand numbers of applications from other sources and could provide a widevariety of other functions for the user. In some examples, the clientdevices 14(1)-14(n) comprise mobile devices with Internet access thatenable web pages and other content stored by the server devices16(1)-16(n) to be retrieved and rendered. By way of example only, theclient devices 14(1)-14(n) can be smart phones, personal digitalassistants, tablets, or computers.

Each of the client devices 14(1)-14(n) includes a processor, a memory,an input device, a display device, and a communication interface, whichare coupled together by a bus or other link, although one or more ofclient devices 14(1)-14(n) can include other numbers and types ofcomponents, parts, devices, systems, and elements in otherconfigurations. The processor in each of the client devices 14(1)-14(n)can execute a program of instructions stored in the memory the clientdevice 14(1)-14(n) for one or more aspects of the present invention, asdescribed and illustrated herein, although the processor could executeother numbers and types of programmed instructions.

The input device in each of the client devices 14(1)-14(n) can be usedto input selections, such as a request for a particular web page orother content stored by one or more of the server devices 16(1)-16(n),although the input device could be used to input other types of requestsand data and interact with other elements. The input device can includekeypads, touch screens, and/or vocal input processing systems, althoughother types and numbers of input devices can also be used.

The display device in each of the client devices 14(1)-14(n) can be usedto show data and information to the user, such as web pages and othercontent retrieved from the server devices 16(1)-16(n) by way of exampleonly. The display device in each of the client devices 14(1)-14(n) canbe a mobile phone screen display, although other types and numbers ofdisplays could be used depending on the particular type of clientdevice.

The communication interface in each of the client devices 14(1)-14(n)can be used to operatively couple and communicate between the clientdevices 14(1)-14(n), web content management server 12, and serverdevices 16(1)-16(n) over the communication networks 18(1)-18(2).

Each of the server devices 16(1)-16(n) provides content including webpages and web applications for use by one or more of the client devices14(1)-14(n) via the web content management server 12, although theserver devices 16(1)-16(n) can provide other numbers and types ofcontent and perform other functions. Each of the server devices16(1)-16(n) can include a processor, a memory, and a communicationinterface, which are coupled together by a bus or other link, althougheach of the server devices 16(1)-16(n) can have other numbers and typesof components, parts, devices, systems, and elements in otherconfigurations.

The processor in each of the server devices 16(1)-16(n) executes aprogram of instructions stored in the memory of the server devices16(1)-16(n) for one or more aspects of the present invention, asdescribed and illustrated by way of the embodiments herein, although theprocessor could execute other numbers and types of programmedinstructions.

The communication interface in each of the server devices 16(1)-16(n) isused to operatively couple and communicate between the server devices16(1)-16(n), the web content management server 12, and the clientdevices 14(1)-14(n) via the communication networks 18(1)-18(2).

Although embodiments web content management server 12, the clientdevices 14(1)-14(n), and the server devices 16(1)-16(n) are describedand illustrated herein, each of the web content management server 12,the client devices 14(1)-14(n), and the server devices 16(1)-16(n) canbe implemented on any suitable computer apparatus or computing device.It is to be understood that the apparatuses and devices of theembodiments described herein are for exemplary purposes, as manyvariations of the specific hardware and software used to implement theembodiments are possible, as will be appreciated by those skilled in therelevant art(s).

Furthermore, each of the devices of the embodiments may be convenientlyimplemented using one or more general purpose computers,microprocessors, digital signal processors, and micro-controllers,programmed according to the teachings of the embodiments, as describedand illustrated herein, and as will be appreciated by those ordinaryskill in the art.

In addition, two or more computing apparatuses or devices can besubstituted for any one of the devices in any embodiment describedherein. Accordingly, principles and advantages of distributedprocessing, such as redundancy and replication also can be implemented,as desired, to increase the robustness and performance of the devices ofthe embodiments. The embodiments may also be implemented on computerapparatuses or devices that extend across any suitable network using anysuitable interface mechanisms and communications technologies, includingby way of example only telecommunications in any suitable form (e.g.,voice and modem), wireless communications media, wireless communicationsnetworks, cellular communications networks, G3 communications networks,Public Switched Telephone Network (PSTNs), Packet Data Networks (PDNs),the Internet, intranets, and combinations thereof.

The embodiments may also be embodied as one or more non-transitorycomputer readable medium having instructions stored thereon for one ormore aspects of the present invention as described and illustrated byway of the embodiments herein, as described herein, which when executedby a processor, cause the processor to carry out the steps necessary toimplement the methods of the embodiments, as described and illustratedherein.

An exemplary method for extending a selector application programminginterface (API) will now be described with reference to FIGS. 1-7.Referring more specifically to FIG. 2, a flow chart of an exemplarymethod for extending the selector API to an emulated JavaScriptenvironment is illustrated. In this example, in step 200, the webcontent management server 12 receives an HTTP request for a web pagefrom one of the client devices 14(1)-14(n) and retrieves the requestedweb page from one of the server devices 16(1)-16(n).

In step 202, the web content management server 12 processes theretrieved web page to generate an XML document object model (DOM) and toremove one or more JavaScript code portions. In this example, the webcontent management server 12 stores the DOM and each of the removedJavaScript portions in the memory 22. Each of the removed JavaScriptportions can be stored as associated with a respective identifier.

Additionally, the web page can be modified by the web content managementserver 12 to insert hidden fields in place of the removed JavaScript.Each of the hidden fields include at least one of the identifiers andare inserted so as to cause the requesting one of the client devices14(1)-14(n) to send one or more of the identifiers in a subsequent HTTPrequest. Optionally, the web page can be further processed to optimizethe web page for a display on the requesting one of the client devices14(1)-14(n) and/or to improve the transmission and/or load time of theweb page, for example, although any other type of processing can also beperformed on the web page.

In step 204, the web content management server 12 sends the processedweb page to the requesting one of the client devices 14(1)-14(n). Oncereceived, the requesting one of the client devices 14(1)-14(n) can loadthe web page in a web browser for example.

In step 206, the web content management server 12 receives an HTTPrequest which includes the identifier from the requesting one of theclient devices 14(1)-14(n) in response to a user interaction with theweb page. For example, the user may submit login credentials using asubmit button which prompts the requesting one of the client devices14(1)-14(n) to generate and send an HTTP request including one of theidentifiers previously included in a tag associated with the submitbutton in step 202. In response to receiving the HTTP request, the webcontent management server 12 retrieves the JavaScript code correspondingto the identifier included in the request from the memory 22.

In step 208, the web content management server 12 executes the retrievedJavaScript code on behalf of the requesting one of the client devices14(1)-14(n) in an emulated JavaScript environment. The emulatedJavaScript environment essentially emulates the web browser environmentof the requesting one of the client devices 14(1)-14(n). Methods anddevices for utilizing an emulated JavaScript environment are describedin U.S. patent application Ser. No. 12/802,670 entitled “Methods forutilizing a javascript emulator in a web content proxy server anddevices thereof,” which is incorporated herein by reference in itsentirety.

During execution of the JavaScript code, the web content managementserver 12 determines, in step 210, whether a cascading stylesheet (CSS)selector expression is encountered. CSS selector expressions include aquerySelector( ) or querySelectorAll( ) function call in this exampleand a plurality of expression components, although the CSS selectorexpressions could include other function calls and other content. Eachof the querySelector( ) and querySelectorAll( ) functions are defined inthe selector API and receive at least one CSS selector as a parameter.If the web content management server 12 determines that a CSS selectorexpression has been encountered, then the Yes branch is taken to step212.

While steps 200-212 are illustrated for exemplary purposes, othermethods of encountering or receiving a CSS selector expression can beused. Additionally, other types of environments other than an emulatedJavaScript environment can be used. For example, the methods and devicesdescribed and illustrated herein are operable with any browser emulatorexecuted on a web content management server in which the DOM for eachretrieved web page is implemented using an XML DOM implementation pairedwith an XPath processor.

In step 212, the web content management server 12 extracts an expressioncomponent from the CSS selector expression, and more particularly, fromthe CSS selector(s) included as parameters in the CSS selectorexpression. One exemplary expression component can be “div.red” (e.g.,as part of a CSS selector expression “querySelectorAll(‘div.red’)”).This expression component would require selecting all the “div” elementsof the DOM generated in step 202 having a class attribute containing“red”. Other expression components can also be extracted in step 212.

In step 214, the web content management server 12 determines whether anequivalent XML path language (XPath) expression can be generated for theextracted expression component. The determination can be made based on astored mapping of expression component formats or types to equivalentXPath expressions, for example, although other methods of determiningwhether the expression component has an equivalent XPath expression canalso be used. In this example, the “div.red” expression component isequivalent to the “//div[contains(concat(“, @class, ”), ‘red’)]” XPathexpression. Accordingly, if the web content management server 12determines that an equivalent XPath expression can be generated for theexpression component, then the Yes branch is taken to step 216.

In step 216, the web content management server 12 generates theequivalent XPath expression from the expression component. Optionally,the web content management server 12 also stores the equivalent XPathexpression at least temporarily in the memory 22.

In step 218, the web content management server 12 determines whetherthere are more expression components that can be extracted from the CSSselector expression. If the web content management server 12 determinesthere are more expression components that can be extracted from the CSSselector expression, then the Yes branch is taken back to step 212 andanother expression component is extracted, as described and illustratedearlier.

The web content management server 12 then determines in step 214 whetheran equivalent XPath expression can be generated for the extractedexpression component, also as described and illustrated earlier. In thisiteration, the exemplary extracted expression component is“.red:nth-of-type(odd)”. This exemplary expression component wouldrequire selecting all the elements of the DOM generated in step 202having a class attribute containing “red” and being in an odd positionin the set of all children of the element's parents having the same nameas the element. In this example, the :nth-of-type pseudo class does nothave an equivalent XPath expression. Accordingly, in this iteration, theweb content management server 12 determines in step 214 that anequivalent XPath expression cannot be generated for the extractedexpression component and the No branch is taken to step 220.

In step 220, the web content management server 12 transforms theexpression component into a transformed expression including at leastone XPath expression and at least one extension function. Optionally,the web content management server 12 also stores the transformedexpression at least temporarily in the memory 22. The extensionfunctions in this example are custom functions written in Java,optionally defined in a file stored in the memory 22, and associatedwith an XPath processor of the web content management server 12. Theextension functions can be mapped to one or more psuedo classes in thememory 22 and selected for a particular transformation based on themapping.

Optionally, the extension functions are prefixed by a namespace whichfacilitates locating of the extension functions by the XPath processor.Also optionally, the transformed expression can include a mathematicaloperation (e.g., in order to implement an “odd” parameter of the psuedoclass of the expression component). An exemplary set of extensionfunctions is described and illustrated in more detail later withreference to FIGS. 3-7.

In this example, the expression component can be transformed into atransformed expression including “//*[contains(concat(“, @class, ”),‘red’)][expr:css-type-position(.) mod 2=1]”. Accordingly, in thisexample, the XPath expression of the transformed expression includes“//*[contains(concat(“, @class, ”), ‘red’)]”. The extension function ofthe transformed expression in this example is the “css-type-position( )”extension function, although other extension functions with differentnames can also be used.

The extension function in this example takes in an indication of anelement of the DOM as a parameter (or “.” which indicates all elementsas used in this example), although other parameters can also be used. Inthis example, “expr:” is used as a namespace prefix, although anynamespace prefix can be used. Additionally, a modulus operation andcomparison is performed on the result of the execution of the extensionfunction in this example, although other mathematical or logicaloperations can also be used.

In step 218, the web content management server 12 determines whetherthere are any more expression components in the CSS selector expression,as described and illustrated earlier. If the web content managementserver 12 determines there are no more expression components in thisiteration, then the No branch is taken to step 222.

In step 222, the web content management server 12 generates a combinedexpression including at least all of the transformed expressions andgenerated equivalent XPath expressions optionally stored in the memory22 in steps 216 and step 220. In this example, the expressions can bemerged together using the XPath operators corresponding to the CSSdescendants operators, for example, although other operators and methodsof combining the expressions can also be used.

In step 224, the web content management server 12 applies the combinedexpression to the DOM, generated in step 202 and corresponding to theweb page, to generate a result. The result can be a set of elements ofthe DOM that satisfy or correspond to the CSS selector expressionencountered in step 210, although other types and numbers of results arealso possible. Subsequent to applying the combined in expression to theDOM or, referring back to step 210, if the web content management server12 determines during execution of the JavaScript code in step 208 that aCSS selector expression has not been encountered and the No branch istaken, the web content management server proceeds to step 226.

In step 226, the web content management server 12 determines whetherexecution of the retrieved JavaScript has completed. If the web contentmanagement server 12 proceeds to step 226 subsequent to applying thecombined expression to the DOM in step 224, it is likely that executionof the JavaScript is not complete. Accordingly, in these examples, theNo branch is taken back to step 208 and the web content managementserver 12 continues executing the JavaScript retrieved in step 206.Additionally, the result generated in step 224 can be used by theJavaScript in these examples such as to manipulate, filter, perform anoperation on, or reduce the DOM elements indicated therein. During thecontinued execution of the JavaScript code, the web content managementserver 12 again proceeds to step 210 in a subsequent iteration, asdescribed and illustrated earlier.

However, if the No branch is taken from step 210, execution of theJavaScript is likely complete and no CSS selector expressions wereencountered, or no additional CSS selector expression subsequent to aprior iteration of steps 214-224 was encountered. Accordingly, in theseexamples, the Yes branch is taken from step 226 to step 228. In step228, the web content management server 12 sends a response to the HTTPrequest received in step 206 to the requesting one of the client devices14(1)-14(n). The contents of the HTTP response can be based on theexecution of the JavaScript code, for example, including any CSSselector expressions embedded therein.

Referring to FIGS. 3-7, exemplary methods performed by an exemplary setof extension functions when executed during the application of thecombined expression to the DOM in step 224 is illustrated. The extensionfunctions can be executed by an XPath processor, which is optionallypart of an extensible stylesheet language (XSL) processor, of the webcontent management server 12, for example, although other methods ofexecuting the extension functions can also be used.

Referring more specifically to FIG. 3, a flow chart of an exemplarymethod performed by an extension function for evaluating the:first-of-type, :last-of-type, :nth-of-type, and :nth-last-of-typepseudo classes is illustrated. In step 300, the web content managementserver 12 receives an indication of a DOM element, such as passedthrough a parameter of the extension function. In this example, theextension function can be the “css-type-position(element)” extensionfunction identified earlier for evaluating the :nth-of-type pseudo classof the “.red:nth-of-type(odd)” expression component of the exampledescribed and illustrated earlier, although any other name can be usedfor the extension function.

In step 302, the web content management server 12 instantiates avariable T having a value of the tag name of the DOM element received instep 300. In step 304, the web content management server 12 instantiatesa variable C having a value of 1. Other variables and variable names canalso be used.

In step 306, the web content management server 12 determines whetherthere are any preceding siblings in the DOM of the DOM element receivedin step 300. If the web content management server 12 determines thereare any preceding siblings in the DOM, then the Yes branch is taken tostep 308. In step 308, the web content management server 12 determineswhether one of the preceding siblings is an element and has a tag nameequal to T. If the web content management server 12 determines that thepreceding sibling is an element and has a tag name equal to T, then theYes branch is taken to step 310. In step 310, the web content managementserver 12 increments the value of C. If the web content managementserver 12 determines that the preceding sibling is not an element ordoes not have a tag name equal to T, then the No branch is taken back tostep 306.

In a subsequent iteration of step 306 in this example, the web contentmanagement server 12 again determines whether there are any additionalpreceding siblings of the element that have not yet been considered. Ifthe web content management server 12 determines there is not anyadditional preceding siblings, then the No branch is taken to step 312.In step 312, the web content management server 12 returns the value ofC. The returned value can be used to continue evaluating the combinedexpression applied to the DOM, for example. Accordingly, the extensionfunction in this example returns a number of preceding sibling elementsof the element of the DOM having the same tag name as the element plusone.

Referring more specifically to FIG. 4, a flow chart of an exemplarymethod performed by an extension function for evaluating the:last-of-type, :only-of-type, and :nth-last-of-type pseudo classes isillustrated. In step 400, the web content management server 12 receivesan indication of a DOM element, such as passed through a parameter ofthe extension function. In this example, the extension function can be a“css-type-total(element)” extension function, although any other namecan be used for the extension function.

In step 402, the web content management server 12 instantiates avariable T having a value of the tag name of the DOM element received instep 400. In step 404, the web content management server 12 instantiatesa variable C having a value of 0. Other variables and variable names canalso be used.

In step 406, the web content management server 12 determines whetherthere are any children in the DOM of the parent of the DOM elementreceived in step 400 or, alternatively, any siblings of the DOM element.If the web content management server 12 determines there are children ofthe parent of the DOM element, then the Yes branch is taken to step 408.In step 408, the web content management server 12 determines whether oneof the children is an element and has a tag name equal to T. If the webcontent management server 12 determines that the child is an element andhas a tag name equal to T, then the Yes branch is taken to step 410. Instep 410, the web content management server 12 increments the value ofC. If the web content management server 12 determines that the child isnot an element or does not have a tag name equal to T, then the Nobranch is taken back to step 406.

In a subsequent iteration of step 406 in this example, the web contentmanagement server 12 again determines whether there are any additionalchildren of the parent of the element that have not yet been considered.If the web content management server 12 determines there is not anyadditional children, then the No branch is taken to step 312. In step312, the web content management server 12 returns the value of C. Thereturned value can be used to continue evaluating the combinedexpression applied to the DOM, for example. Accordingly, the extensionfunction in this example returns a number of child elements of theparent of the element of the DOM having the tag name one of the element.

Referring more specifically to FIG. 5, a flow chart of an exemplarymethod performed by an extension function for evaluating the :langpseudo class is illustrated. In step 500, the web content managementserver 12 receives an indication of a DOM node, such as passed through aparameter of the extension function. In this example, the extensionfunction can be a “lang(node)” extension function, although any othername can be used for the extension function.

In step 502, the web content management server 12 instantiates avariable N having a value indicating the node received in step 500. Instep 504, the web content management server 12 instantiates a variable Lhaving a value of ‘en’ or any other default indication of a language.Other variables and variable names can also be used.

In step 506, the web content management server 12 determines whether Nindicates a node that is an element. If the web content managementserver 12 determines N indicates a node that is an element, then the Yesbranch is taken to step 508. In step 508, the web content managementserver 12 determines whether the node indicated by N has a languageattribute. If the web content management server 12 determines that thenode indicated by N does not have a language attribute, then the Nobranch is taken to step 510.

In step 510, the web content management server 12 sets the value of N toindicate the parent of the node indicated by the current value of N. Theweb content management server 12 then proceeds back to step 506 andagain determines whether N indicates a node that is an element.Referring back to step 508, if the web content management server 12determines that the node indicated by N does have a language attribute,then the Yes branch is taken to step 512.

In step 512, the value of L is assigned the value of the languageattribute of the node indicated by N. In step 514, the web contentmanagement server 12 returns the value of L. Referring back to step 506,if the web content management server 12 determines in a first orsubsequent iteration that N indicates a node that is not an element,then the No branch is taken to step 514 and the default value of L isreturned. The returned value can be used to continue evaluating thecombined expression applied to the DOM, for example. Accordingly, theextension function in this example returns a value of a first identifiedlanguage attribute based on a traversal of the element of the DOM andany ancestors of the element of the DOM.

Referring more specifically to FIG. 6, a flow chart of an exemplarymethod performed by an extension function for evaluating the :not pseudoclass is illustrated. In step 600, the web content management server 12receives an indication of a DOM element and a string including a CSSselector expression, such as passed through a parameter of the extensionfunction. In this example, the extension function can be a“filter-out(element, css-selector)” extension function, although anyother name can be used for the extension function.

In step 602, the web content management server 12 applies the receivedCSS selector expression to the DOM to generate a result, such asdescribed and illustrated earlier with reference to steps 210-224, forexample, although other methods of evaluating the received CSS selectorexpression can also be used. In this example, the CSS selectorexpression includes a CSS selector function querySelectorAll( ) althoughother functions can also be included in the CSS selector expression ofthe string received in step 600.

In step 604, the web content management server 12 determines whetherthere are any nodes in the result generated by the application of theCSS selector expression in step 602. If the web content managementserver 12 determines there are node(s) in the result, then the Yesbranch is taken to step 606. In step 606, the web content managementserver 12 determines whether one of the node(s) in the result is equalto the DOM element received in step 600. If the web content managementserver 12 determines that the one of the node(s) in the result is equalto the DOM element, then the Yes branch is taken to step 608. In step608, the web content management server 12 returns a value of false.

Referring back to step 606, if the web content management server 12determines that the one of the node(s) in the result is not equal to theDOM element, then the No branch is taken back to step 604. If the webcontent management server 12 determines in step 604 that the no nodes inthe result of the evaluation of the CSS selector expression, or noadditional nodes not previously considered, then the No branch is takento step 610. In step 610, the web content management server 12 returns avalue of true. Accordingly, the extension function in this examplereturns a true value when the element of the DOM received in step 600 isnot included in a result obtained by applying the CSS selectorexpression received in step 600 and a false value when the element ofthe DOM is included in the result.

Referring more specifically to FIG. 7, a flow chart of an exemplarymethod performed by an extension function for evaluating the :selectedjQuery pseudo class is illustrated. In step 700, the web contentmanagement server 12 receives an indication of a DOM option element,such as passed through a parameter of the extension function. In thisexample, the extension function can be an “option-selected(option)”extension function, although any other name can be used for theextension function. The indication of the option element can representan option in a dropdown list in an HTML form, for example, although theoption can also refer to other types of elements.

In step 701, the web content management server 12 determines whether theoption is explicitly selected. If the web content management server 12determines that the option is explicitly selected, then the Yes branchis taken to step 704. In step 704, the web content management serverreturns a value of true. Referring back to step 702, if the web contentmanagement server 12 determines that the option is not explicitlyselected, then the No branch is taken to step 706.

In step 706, the web content management server 12 obtains a selectelement from the DOM that contains the option element corresponding tothe indication received in step 700. In step 708, the web contentmanagement server 12 determines whether the select element is a singleselection element with size attribute equal to 1. If the web contentmanagement server 12 determines that the select element is a singleselection element with size attribute equal to 1 then the Yes branch istaken to step 210.

In step 710, the web content management server 12 determines whether theoption element corresponding to the indication received in step 700 isthe first option element descendant of the select element. If the webcontent management server 12 determines that the option element is thefirst option element descendant of the select element, then the Yesbranch is taken to step 712.

In step 712, the web content management server 12 determines whether allof the other option elements descendant from the select element are notselected. If the web content management server 12 determines that all ofthe other option elements descendant from the select element are notselected then the Yes branch is taken to step 714. In step 714, the webcontent management server 12 returns a value of true.

Referring back to steps 708, 710, and 712, if the web content managementserver determines that the select element is not a single selectionelement or does not have a size attribute equal to 1, the option elementcorresponding to the indication received in step 700 is not the firstoption element descendant of the select element, or any of the otheroption elements descendant from the select element are selected,respectively, then one of the respective No branches is taken to step716. In step 716, the web content management server 12 returns a valueof false. Accordingly, the extension function in this example returns atrue value if the option element of the DOM is selected and a falsevalue if the option element of the DOM is not selected. In this example,the option is considered selected if it is explicitly selected or if itis the first option of a select element that has no explicitly selectedoptions and is not a multiple selections select element.

With this technology, web page scripts including JavaScript code can beemulated by a web content management server on behalf of client devicesthat may not otherwise be able to take advantage of such functionality.Advantageously, any CSS selector expressions embedded in the JavaScriptcan be translated to XPath expressions based on an equivalent XPathexpression or, in the case of CSS selector expressions withoutequivalent XPath expressions, by using an extension function. Thereby,CSS selector expressions can be fully translatable to XPath expressionsand implemented using a relatively efficient XPath processor without thesignificant additional code and associated complexity required toimplement the CSS selector expressions of the selector API.

Having thus described the basic concept of the invention, it will berather apparent to those skilled in the art that the foregoing detaileddisclosure is intended to be presented by way of example only, and isnot limiting. Various alterations, improvements, and modifications willoccur and are intended to those skilled in the art, though not expresslystated herein. These alterations, improvements, and modifications areintended to be suggested hereby, and are within the spirit and scope ofthe invention. Additionally, the recited order of processing elements orsequences, or the use of numbers, letters, or other designationstherefore, is not intended to limit the claimed processes to any orderexcept as may be specified in the claims. Accordingly, the invention islimited only by the following claims and equivalents thereto.

What is claimed is:
 1. A method for extending a selector applicationprogramming interface (API), the method comprising: receiving, by a webcontent management server, a cascading style sheet (CSS) selectorexpression comprising a plurality of expression components; determining,by the web content management server, when an equivalent XML pathlanguage (XPath) expression can be generated for each of the expressioncomponents; and transforming, by the web content management server, eachof the expression components for which the determining indicates that anequivalent XPath expression cannot be generated into a transformedexpression comprising at least one XPath expression and an extensionfunction.
 2. The method of claim 1 further comprising generating, withthe web content management server, the equivalent XPath expression foreach of the plurality of expression components for which the determiningindicates that an equivalent XPath expression can be generated.
 3. Themethod of claim 2 further comprising: generating, by the web contentmanagement server, a combined expression comprising each of thetransformed expression components and each of the equivalent XPathexpressions; and applying, by the web content management server, thecombined expression to a document object model (DOM) to generate aresult.
 4. The method of claim 3 wherein the extension functioncomprises JavaScript code and the applying further comprises executingthe extension function in an emulated JavaScript environment.
 5. Themethod of claim 3 wherein: at least one of the expression components forwhich the determining indicates that an equivalent XPath expressioncannot be generated comprises a pseudo class comprising :first-of-type,:last-of-type, :nth-of-type, or :nth-last-of-type; and the extensionfunction of the transformed expression for the at least one of theexpression components is configured to receive an indication of anelement of the DOM, the indication comprising a tag name of the elementof the DOM, and return a number of one or more preceding siblingelements of the element of the DOM having the tag name.
 6. The method ofclaim 3 wherein: at least one of the expression components for which thedetermining indicates that an equivalent XPath expression cannot begenerated comprises a pseudo class comprising :last-of-type,:only-of-type, or :nth-last-of-type; and the extension function of thetransformed expression for the at least one of the expression componentsis configured to receive an indication of an element of the DOM, theindication comprising a tag name of the element of the DOM and return anumber of child elements of the parent of the element of the DOM havingthe tag name plus one.
 7. The method of claim 3 wherein: at least one ofthe expression components for which the determining indicates that anequivalent XPath expression cannot be generated comprises a :lang pseudoclass; and the extension function of the transformed expression for theat least one of the expression components is configured to receive anindication of an element of the DOM and return a value of a firstidentified language attribute based on a traversal of the element of theDOM and any ancestors of the element of the DOM.
 8. The method of claim3 wherein: at least one of the expression components for which thedetermining indicates that an equivalent XPath expression cannot begenerated comprises a :not pseudo class; and the extension function ofthe transformed expression for the at least one of the expressioncomponents is configured to receive an indication of an element of theDOM and a second CSS selector expression and return a true value whenthe element of the DOM is not included in a second result obtained byapplying the second CSS selector expression and a false value when theelement of the DOM is included in the second result.
 9. The method ofclaim 3 wherein: at least one of the expression components for which thedetermining indicates that an equivalent XPath expression cannot begenerated comprises a :selected jQuery pseudo class; and the extensionfunction of the transformed expression for the at least one of theexpression components is configured to receive an option element of theDOM and return a true value if the option element of the DOM is selectedand a false value if the option element of the DOM is not selected. 10.A non-transitory computer readable medium having stored thereoninstructions for extending a selector application programming interface(API) comprising machine executable code which when executed by aprocessor, causes the processor to perform steps comprising: receiving acascading style sheet (CSS) selector expression comprising a pluralityof expression components; determining when an equivalent XML pathlanguage (XPath) expression can be generated for each of the expressioncomponents; and transforming each of the expression components for whichthe determining indicates that an equivalent XPath expression cannot begenerated into a transformed expression comprising at least one XPathexpression and an extension function.
 11. The non-transitory computerreadable medium of claim 10 further having stored thereon instructionscomprising machine executable code which when executed by the processor,causes the processor to perform steps further comprising generating theequivalent XPath expression for each of the plurality of expressioncomponents for which the determining indicates that an equivalent XPathexpression can be generated.
 12. The non-transitory computer readablemedium of claim 11 further having stored thereon instructions comprisingmachine executable code which when executed by the processor, causes theprocessor to perform steps further comprising: generating a combinedexpression comprising each of the transformed expressions and each ofthe equivalent XPath expressions; and applying the combined expressionto a document object model (DOM) to generate a result.
 13. Thenon-transitory computer readable medium of claim 12 wherein theextension function comprises JavaScript code and the applying furthercomprises executing the extension function in an emulated JavaScriptenvironment.
 14. The non-transitory computer readable medium of claim 12wherein: at least one of the expression components for which thedetermining indicates that an equivalent XPath expression cannot begenerated comprises a pseudo class selected from :first-of-type,:last-of-type, :nth-of-type, or :nth-last-of-type; and the extensionfunction of the transformed expression for the at least one of theexpression components is configured to receive an indication of anelement of the DOM, the indication comprising a tag name of the elementof the DOM, and return a number of preceding sibling elements of theelement of the DOM having the tag name.
 15. The non-transitory computerreadable medium of claim 12 wherein: at least one of the expressioncomponents for which the determining indicates that an equivalent XPathexpression cannot be generated comprises a pseudo class selected from:last-of-type, :only-of-type, or :nth-last-of-type; and the extensionfunction of the transformed expression for the at least one of theexpression components is configured to receive an indication of anelement of the DOM, the indication comprising a tag name of the elementof the DOM and return a number of child elements of the parent of theelement of the DOM having the tag name plus one.
 16. The non-transitorycomputer readable medium of claim 12 wherein: at least one of theexpression components for which the determining indicates that anequivalent XPath expression cannot be generated comprises a :lslangpseudo class; and the extension function of the transformed expressionfor the at least one of the expression components is configured toreceive an indication of an element of the DOM and return a value of afirst identified language attribute based on a traversal of the elementof the DOM and any ancestors of the element of the DOM.
 17. Thenon-transitory computer readable medium of claim 12 wherein: at leastone of the expression components for which the determining indicatesthat an equivalent XPath expression cannot be generated comprises a :notpseudo class; and the extension function of the transformed expressionfor the at least one of the expression components is configured toreceive an indication of an element of the DOM and a second CSS selectorexpression and return a true value when the element of the DOM is notincluded in a second result obtained by applying the second CSS selectorexpression and a false value when the element of the DOM is included inthe second result.
 18. The non-transitory computer readable medium ofclaim 12 wherein: at least one of the expression components for whichthe determining indicates that an equivalent XPath expression cannot begenerated comprises a :selected jQuery pseudo class; and the extensionfunction of the transformed expression for the at least one of theexpression components is configured to receive an option element of theDOM and return a true value if the option element of the DOM is selectedand a false value if the option element of the DOM is not selected. 19.A management server device, comprising: a memory comprising programmedinstructions stored in the memory and a hardware processor executing theprogrammed instructions stored in the memory to: receive a cascadingstyle sheet (CSS) selector expression comprising a plurality ofexpression components; determine when an equivalent XML path language(XPath) expression can be generated for each of the expressioncomponents; and transform each of the expression components for whichthe determining indicates that an equivalent XPath expression cannot begenerated into a transformed expression comprising at least one XPathexpression and an extension function.
 20. The management server deviceof claim 19 wherein the hardware processor further executing theprogrammed instructions stored in the memory generating to generate theequivalent XPath expression for each of the plurality of expressioncomponents for which the determining indicates that an equivalent XPathexpression can be generated.
 21. The management server device of claim20 wherein the hardware processor further executing the programmedinstructions stored in the memory comprising to: generate a combinedexpression comprising each of the transformed expressions and each ofthe equivalent XPath expressions; and apply the combined expression to adocument object model (DOM) to generate a result.
 22. The managementserver device of claim 21 wherein the extension function comprisesJavaScript code and the hardware processor further executing theprogrammed instructions stored in the memory to execute the extensionfunction in an emulated JavaScript environment.
 23. The managementserver device of claim 21 wherein: at least one of the expressioncomponents for which determining indicates that an equivalent XPathexpression cannot be generated comprises a pseudo class selected from:first-of-type, :last-of-type, :nth-of-type, or :nth-last-of-type; andthe extension function of the transformed expression for the at leastone of the expression components is configured to receive an indicationof an element of the DOM, the indication comprising a tag name of theelement of the DOM, and return a number of preceding sibling elements ofthe element of the DOM having the tag name.
 24. The management serverdevice of claim 21 wherein: at least one of the expression componentsfor which determining indicates that an equivalent XPath expressioncannot be generated comprises a pseudo class selected from:last-of-type, :only-of-type, or :nth-last-of-type; and the extensionfunction of the transformed expression for the at least one of theexpression components is configured to receive an indication of anelement of the DOM, the indication comprising a tag name of the elementof the DOM and return a number of child elements of the parent of theelement of the DOM having the tag name plus one.
 25. The managementserver device of claim 21 wherein: at least one of the expressioncomponents for which determining indicates that an equivalent XPathexpression cannot be generated comprises a :lang pseudo class; and theextension function of the transformed expression for the at least one ofthe expression components is configured to receive an indication of anelement of the DOM and return a value of a first identified languageattribute based on a traversal of the element of the DOM and anyancestors of the element of the DOM.
 26. The management server device ofclaim 21 wherein: at least one of the expression components for whichdetermining indicates that an equivalent XPath expression cannot begenerated comprises a :not pseudo class; and the extension function ofthe transformed expression for the at least one of the expressioncomponents is configured to receive an indication of an element of theDOM and a second CSS selector expression and return a true value whenthe element of the DOM is not included in a second result obtained byapplying the second CSS selector expression and a false value when theelement of the DOM is included in the second result.
 27. The managementserver device of claim 21 wherein: at least one of the expressioncomponents for which determining indicates that an equivalent XPathexpression cannot be generated comprises a :selected jQuery pseudoclass; and the extension function of the transformed expression for theat least one of the expression components is configured to receive anoption element of the DOM and return a true value if the option elementof the DOM is selected and a false value if the option element of theDOM is not selected.